Dynamic sole

ABSTRACT

A sole for use in footwear that includes an upper surface for contacting the user&#39;s foot and a lower surface for engaging a walking surface. The sole extends beneath the heel through the ankle/sub-talar complex and metatarsal head of the user. The lower surface is characterized as having a convex lower surface beneath the ankle/sub-talar complex curving upwardly toward the heel and metatarsal head.

TECHNICAL FIELD

The present invention involves a sole capable of being incorporated in a variety of footwear applications including shoes, sandals and slippers (collectively referred to as “shoes”). When properly incorporated within a shoe, the present invention provides motion enhancement for the human foot to improve posture, comfort, support and to eliminate shock.

BACKGROUND OF THE INVENTION

Although there have been a plethora of soles and orthotic inserts alleged to improve the acts of walking, standing, exercising and load bearing in order to provide decreased stress and skeletal alignment, there has been no system that can be characterized as representing a paradigm change in foot function from resistance to acceleration and from motion control to motion enhancement. Traditional orthotic devices and shoes employing them use firm materials to support the foot and cushion materials for shock absorption that protect the foot from hard surfaces. Comfort is based on the cushioning or support or a combination depending on the environment and activities.

In this regard, reference is made to FIG. 1 which depicts the typical dynamics of foot and leg motion when taking a step in pre-existing footwear. As noted, leg 10 supports a foot contained within shoe 11. As a step is taken, heel 15 begins to engage surface 14. As this occurs, the longitudinal axis 12 running down leg 10 is perpendicular to the longitudinal axis 13 of the foot contained within shoe 11. As the totality of shoe 11 comes into full contact engagement with support surface 14, the angle between longitudinal axes 12 and 13 expands approximately 15 degrees. This expansion is done through the ankle and sub-talar joints. Next, shoe 11 again being flush with surface 14 supports leg 10 in an upright fashion returning the angle between axes 12 and 13 to one which is perpendicular or 90 degrees. As the stepping function continues, leg 10 then moves forward as one begins to step off from support surface 14. When this occurs, longitudinal axes 12 and 13 form an acute angle, that is, less than 90 degrees, and, generally, about 80 degrees. Finally, the step-off motion continues as leg 10 bends at the knee, heel 15 is lifted from surface 14 and push-off is created through the metatarsal region.

From a review of the walking motion depicted in FIG. 1, several things become readily apparent. Initiating walking motion creates initial heel impact as heel 15 of shoe 11 engages surface 14. Next, the downward ankle motion through the sub-talar joint creates fatigue. As the step-off motion is initiated, stress is created through the toe joints, hallux limitus causing bunions, metatarsalgia, capsulitis and hammertoes. Again, there has been no suggestion to date as how one would change the walking dynamic shown in FIG. 1 to alleviate these concerns.

It is thus an object of the present invention to provide a new sole for a shoe capable of improving the walking motion providing the user with attendant benefits heretofore being unavailable.

These and further objects will be more readily apparent when considering the following disclosure and appended claims.

SUMMARY OF THE INVENTION

A sole for use in footwear comprising a foot cradle for contacting the user's foot and a rocker bottom for engaging a walking surface, said sole extending beneath the heel through the ankle/sub-talar complex and metatarsal head of a user, said rocker bottom being characterized as having a convex lower surface beneath the ankle/sub-talar complex curving upwardly towards said heel and said metatarsal head. The present invention supports the four major arches of the foot, eliminates step shock, controls frontal plane motion, transfers motion from the heel to ankle at the sub-talar joint and ankle to forefoot at the metatarsal joint.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic illustration showing the interaction between the leg and foot of a walker employing a traditional shoe.

FIG. 2 is a side view showing the skeletal components of the human foot as well as the alignment of this foot to the dynamic sole of the present invention.

FIG. 3A is a side exploded view of the dynamic sole of the present invention depicting its various elements.

FIG. 3B is a side view of what is referred to as the high rocker version of the present invention.

FIG. 4 is a schematic depiction of one's walking motion in comparison to the schematic illustrations of FIG. 1, in this instance, employing a shoe having the dynamic sole of the present invention.

FIG. 5 is a side plan view depicting an embodiment of the present invention whereby a frame structure is employed to maintain the intended shape of the dynamic sole.

DETAILED DESCRIPTION OF THE INVENTION

As noted previously with respect to the discussion of FIG. 1, the typical walking motion in prior footwear on hard flat surfaces creates impact shock and rapid downward flexion of the foot as body weight passes from heel to toe through the sub-talar, ankle, and mid-tarsal joints until the forefoot impacts and pushes off through the weight bearing metatarsal bones. The most common heel, ankle, and forefoot problems such as heel spurs, plantar fasciitis, ankle arthritis, tendonitis, metatarsalgia, capsulitis, sesamoiditis, bunions, hallux rigidus, and hammertoes are caused by walking on hard surfaces with a heeled shoe. Of primary concern is the recognition that prior footwear causes the bones of the foot and ankle to undergo greater impact and joint distortion than walking barefoot on soft surfaces.

The present invention can be more readily appreciated when considering FIG. 1 in conjunction with the depiction of human foot 30 of FIG. 2. FIG. 2 shows curved shapes I, II, and III known as “rockers of the foot” (A, B and C are known as “rockers of the sole”). As background, during the swing phase of walking, the foot lands in relaxed supination. Just before contact, the foot dorsiflexes at the ankle to clear the ground. At heel contact (rocker I), these dynamics change. Actions are reactive to absorb shock and maintain balance. On contact, the heel hits the outside of the center with the foot slightly toed out. Immediately thereafter, the shock of impact is dissipated by pronation of the foot to adapt it to the support surface and to maintain balance noting that this contact phase is also known as the resistance phase. Upon forefoot contact, the resistance phase ends as stress (center of pressure) passes over rocker II, the ankle/sub-talar complex. On foot contact, the rebound force through the midfoot meets the downward force of body weight within the base support as the center of pressure passes through the metatarsal heads (rocker III). As pressure passes the metatarsals, if they are stable, windlass action of the plantar fascia pulls and elevates the heel as the heel leaves the ground in the lift-off phase.

These dynamic actions result, as noted above, in heel impact (rocker I), ankle maladies (rocker II) and stress to toe joints (rocker III). The present invention comprises sole 21 intended to extend from heel 32 through ankle/sub-talar complex beneath the sub-talar joint 31 and metatarsal head 33 ending proximate toes 34. In order to appreciate the present invention more fully, dynamic sole 21 is shown in FIG. 2 positioned below foot 30 as foot 30 is prepared to step onto and be supported by dynamic sole 21. In this regard, dynamic sole 21 is segmented into subparts A, B, and C.

Sole 21 includes foot cradle portion 40 which is intended to contact user's foot 30. Foot cradle portion 40 can consist of a cushioning material such as commonly used in shoes such as EVA (ethylene vinyl acetate), polyurethane, rubber, neoprene™ and poron™ and can have an arched upper surface 41 to conform to the arch of a user's foot for added comfort and support. Of paramount importance in considering the present invention is the shape of lower surface 45 of rocker bottom 50 shown in FIGS. 2 through 5.

Rocker bottom 50, as noted in FIG. 2, extends from heel 32 beneath rocker I constituting subsection A thereof. This portion of rocker bottom 50 transitions into subpart B located beneath sub-talar joint 31 and ankle joint 35 and, in doing so, lies beneath rocker II. Subpart B of dynamic sole 50 then transitions into subsection C located beneath rocker III, or, in other words, beneath the metatarsal head. Lower surface 45 of rocker bottom 50 provides a convex or flat plane lower surface beneath sub-talar joint 31 in the area depicted as subpart B. Further, lower surface 45 curves upwardly from subpart B to subparts A and C, the latter beneath heel portion 32 and metatarsal portion 33 of foot 30, these curved portions being tilted at least approximately 20 degrees from subpart B towards the above-referenced heel and metatarsal head regions indicating as angles theta and theta prime, respectively. In order to maintain this shape, rocker bottom 50 should comprise material capable of retaining its shape upon multiple uses. Suitable material includes etheylene vinyl acetate, for example.

To fully appreciate the benefits inherent in the sole of the present invention, reference is made to FIG. 4. As is the case with FIG. 1, the stepping motion is depicted schematically, in this instance showing leg 10 in conjunction with shoe 20 having dynamic sole 21 of the present invention. As was the case with regard to FIG. 1, the walking motion begins with the heel of shoe 20 impacting surface 14 noting the perpendicular relationship between longitudinal axes 12 and 13 of leg 10 and the foot of the user, respectively. However, unlike the schematic shown in FIG. 1, as the stepping motion continues, longitudinal axes 12 and 13 remain perpendicular to one another as the foot of the user contained in shoe 20 “rocks” through the stepping and walking motion along dynamic sole 21 from heel impact through toe liftoff. This represents a paradigm change in foot function from resistance to acceleration, from motion control to motion enhancement. Dynamic sole 21 alters heel contact, ankle motion and pressure on the forefoot, relieving a multitude of postural conditions. Rocker bottom 50 ideally being at least one-quarter inch thicker in subpart B (beneath sub-talar joint 31) creates a convex or flat lower surface and, this in conjunction with the turned-up lower surfaces in subparts A and B results in decreased heel impact and a reduction in stress over both the ankle joint and metatarsal regions of the foot. As such, the present invention's dynamic rocker sole bottom enhances heel, ankle and metatarsal movement in the sagittal plane while the foot cradle controls foot motions, pronation and supination in the frontal plane.

As noted with respect to FIG. 4, the dynamic sole of the present invention provides a rolling motion where a previous lever action existed. With normal shoes there are two sounds upon walking, heel and forefoot. With the dynamic sole of the present invention, there is one sound of contact as the foot and shoe move smoothly and quietly over the supporting surface. The result of this configuration is improved foot function with walking, race-walking, running and virtually all forward motion activities. This invention relieves pathomechanics, improves balance and enhances normal biomechanics. Clearly, the motion is smoother resulting in one's immediate recognition that it is easier to walk employing a shoe having the dynamic sole of the present invention.

Further, without departing from the scope of the present invention, it is noted that midsole 60 can be positioned between foot cradle 40 and rocker bottom 50 as shown in FIGS. 3A and 3B. As noted previously, foot cradle 40 is intended to provide a cushioning and arch support function for one's foot. The relatively rigid rocker bottom 50 provides the rocking motion, well described previously. Variable midsole 60 can be configured between these two elements in order to create a variability in the overall thickness of dynamic sole 21. This merely enhances the usability of the present invention in providing various environments for its application. However, the shape of dynamic sole 21 need not be maintained strictly through the use of relatively rigid subparts as suggested above.

In this regard, reference is made to FIG. 5 depicting sole 70 of the present invention illustrating an embodiment in which an internal skeletal substructure can be enveloped therein or external skeletal superstructure to maintain the appropriate shape, particularly the shape of a lower surface 71. As noted, a relatively rigid skeletal arrangement can be contained within the dynamic sole of the present invention showing section 73 located beneath sub-talar joint 31 (FIG. 2) while upturned skeletal portion 72 is intended to reside beneath heel 32 (FIG. 2) and upturned elongated skeletal portion 74 to reside below metatarsal region 33 (FIG. 2). This skeletal arrangement which can be configured out of virtually any rigid plastic or metal subframe can be employed herein without departing from the spirit and scope of this invention.

In viewing the various figures, it is quite apparent that the convex lower portion, described as subpart B of dynamic sole 21 or as shown as skeletal section 73 of dynamic sole 70 is designed to extend along the anticipated width of the sub-talar joint to create a balanced platform or “sweet spot.” Others have suggested a raised point to provide pressure upon one portion of a user's foot but no one, prior to the present invention, has suggested a convex region consisting of a balance platform extending the distance of the sub-talar joint.

Finally, although the present invention is intended to be incorporated with the construction of a total shoe (unibody), the foot cradle certainly can be extended for use as an arch support or applied to a foot prior to slipping the foot into a conventional shoe. All of these iterations of this invention would provide the benefits as outlined previously. Various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims. 

1. A sole for use in footwear comprising an upper surface for contacting the user's foot and a lower surface for engaging a walking surface, said sole extending beneath the heel through the ankle/sub-talar complex and metatarsal head of a user, said lower surface being characterized as having a convex or flat lower surface beneath the ankle/sub-talar complex curving upwardly toward said heel and metatarsal heads.
 2. The sole of claim 1 wherein said upward curve of said convex lower surface is tilted at least approximately 20 degrees toward both said heel and metatarsal head.
 3. The sole of claim 1 wherein said upper surface comprises a cushioning material and an arch to act as a foot cradle to conform to the four major arches of the foot.
 4. The sole of claim 1 wherein said lower surface comprises a rocker bottom comprising a material capable of retaining its shape upon multiple uses.
 5. The sole of claim 4 wherein said rocker bottom is thicker in its portion residing beneath the ankle/sub-talar complex than in those portions residing beneath the heel and metatarsal head.
 6. The sole of claim 1 further comprising a midsole positioned between said upper and lower surfaces.
 7. The sole of claim 6 wherein the thickness of said sole is variable by varying the thickness of said midsole.
 8. A sole for use in footwear comprising an upper surface for engaging a user's foot and a lower surface for engaging a walking surface, said sole extending from the heel through the ankle/sub-talar complex and metatarsal head of the user, said lower surface being characterized as being convex beneath the ankle/sub-talar complex and being curved upwardly toward the heel and metatarsal head.
 9. The sole of claim 8 wherein said upward curve of said convex lower surface is tilted at least approximately 20 degrees toward both said heel and metatarsal head.
 10. The sole of claim 8 wherein said upper surface comprises a cushioning material and an arch to conform to a user's foot.
 11. The sole of claim 8 wherein said lower surface comprises a material capable of retaining its shape upon multiple uses.
 12. The sole of claim 8 wherein a skeletal structure is embedded within or attached to said sole to maintain the shape of said sole upon multiple uses. 